title: Transverse susceptibility as a biosensor for detection of Au-Fe₃O₄ nanoparticle-embedded human embryonic kidney cells.
abstract: We demonstrate the possibility of using a radio-frequency transverse susceptibility (TS) technique based on a sensitive self-resonant tunnel-diode oscillator as a biosensor for detection of cancer cells that have taken up magnetic nanoparticles. This technique can detect changes in frequency on the order of 10 Hz in 10 MHz. Therefore, a small sample of cells that have taken up nanoparticles when placed inside the sample space of the TS probe can yield a signal characteristic of the magnetic nanoparticles. As a proof of the concept, Fe3O4 nanoparticles coated with Au (mean size ~60 nm) were synthesized using a micellar method and these nanoparticles were introduced to the medium at different concentrations of 0.05, 0.1, 0.5, and 1 mg/mL buffer, where they were taken up by human embryonic kidney (HEK) cells via phagocytosis. While the highest concentration of Au-Fe3O4 nanoparticles (1 mg/mL) was found to give the strongest TS signal, it is notable that the TS signal of the nanoparticles could still be detected at concentrations as low as 0.1 mg/mL.
authors.affiliation: Department of Physics, University of South Florida, Tampa, FL 33620, USA. natalie.frey.huls@gmail.com
authors.forename: Natalie Frey
authors.initials: NF
authors.lastname: Huls
authors.forename: Manh-Huong
authors.initials: MH
authors.lastname: Phan
authors.forename: Arun
authors.initials: A
authors.lastname: Kumar
authors.forename: Subhra
authors.initials: S
authors.lastname: Mohapatra
authors.forename: Shyam
authors.initials: S
authors.lastname: Mohapatra
authors.forename: Pritish
authors.initials: P
authors.lastname: Mukherjee
authors.forename: Hariharan
authors.initials: H
authors.lastname: Srikanth
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D058948:Cell Tracking / Q000379:methods*; D002478:Cells, Cultured; D057809:HEK293 Cells; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D010316:Particle Size; D010587:Phagocytosis / Q000502:physiology*
chemical_list: D058185:Magnetite Nanoparticles